The "reasonable expectation of privacy" test, formulated in the 1967 case of Katz v. United States, represents a great touchstone in the law of privacy. Katz is important not only because the test is used to determine when a governmental intrusion constitutes a "search" under the Fourth Amendment; but also because the test has also found its way into state common law, statutes and even the laws of other nations. The credit for the development of the test belongs to counsel for Charles Katz, Harvey (now Judge) Schneider, who presented the test for the first time in his oral argument, not in his briefs. The majority opinion's curious failure to mention the test is explained by the fact that the law clerk responsible for drafting Justice Stewart's majority opinion missed the oral argument. Given this context, the articulation of the test in Justice Harlan's short concurring opinion is all the more remarkable, establishing him as not only a great jurist, but as a judge who knew how to listen.